It lets you specify when exactly and how long the computer can be used - Windows Shareware $32.95.
Timing Tasker is a handy software that help you automatically shutdown, power off, reboot, hibernate, suspend or log off computers at schedule time and execute or prohibit some tasks that you specifies. It gives you different ways to schedule the shutdown event for your needs, such as daily, after a process stops and so on. During the shutdown, it can prompt you by sending message, playing music, etc.

Timing Tasker 2.0 7-Apr-08 English 1.2 MB

With this compact and robust software.It has many features that when you use it,as the followings:Shutdown, restart, standby, and lock your computer or close your monitor at schedule time.Customize prompt message, alarm sound, delay and countdown duration during shutdown. Customize scheduled tasks(include executing program, opening file, open web site, timing shutdown and timing remind) or forbidden tasks(include phohibiting program and prohibiting boot) easily.Connect network atomic clock to check the time and prevent users from modifying the system data and time. Set password to avoid others changing your schedule configuration.Provide security control function, such as password protection, prohibiting to modify regedit , ending program by Task Manager,etc.
Support hotkey and hide main window.